Internal combustion engine



May 31, 1938. v ERNST 2,119,226

. INTERNAL COMBUSTION ENGINE Filed Aug. 2'7, 1936 2 Sheets-Sheet l May 31, 1938. ERNST INTERNAL COMBUSTION ENGINE Filed Aug. 27, 1936 2 SheeLs-Sheet 2 all) Patented May 31-, 193s i d V INTERNAL COMBUSTION ENGINE FritzErnst, Kron shagen, near Kiel, Germany, as-

signor to Fried. Krupp-Germaniawerft Aktiengese'llschaft, .Kiel-Gaarden, Germany Application August 27,

1936, Serial No. 98,127

{ In Germany September 7, 1935 11 Claims.

This invention relates to internal combustion engines of the type in which inlet or outletports are controlled by a ,slide'valve arranged in the cylinder head.

In engines of this type the drawback has appeared that the high cylinder pressure occurring during the combustion and explosion period has to be taken up by the valve control gear.

'Various ways have already been suggested and tried to keep these high pressures temporarily from the actuating members proper, viz. cams or cranks, by means of suitable locking members,

such as slot and crank or crank connections. Withall these known constructions, however, I there still remain parts of the control gear which are stressed by the pressure acting upon the slide valve, forexample at least the link immediately moving the slide valve, and its bearing places. a

, The invention has for its object to relieve also this part of the slide valve gear from injurious forces. I f

In order that the invention may be clearly understood and readily carried into effect, two embodiments of the invention are illustrated by way of example in the accompanying drawings as applied to a vertical two-stroke cycle Diesel engine scavenged in longitudinal direction. In; these drawings v Figure 1 shows the first embodiment by a longitudinal section of the working cylinder,

Figure 2 is the corresponding plan view,. and

Figures 3 and 4 show the otherrembodiment, in views corresponding to Figures I and 2, Figure 4 being a plan view, partly in section.-of the embodiment shown in vertical section in Figure 3.

The cylinder body a has mounted in ita liner b in the lower portion of'which are provided inlet ports for the scavenging airwhile the upper portion has outletports d. The inletports are controlled by the working piston e and the outlet ports 11 by a piston slide valve j'which has the same diameter-as the'workingpiston. Thefuel injectionnozzle 9 is disposed laterally in the cylinder wall at the level of the combustion space h formed between the workingpiston e and the piston slide valve 1.

The piston slidevvalve f is actuated by a cam shaft i by means of a two-armed bifurcated lever I formly distributed on its periphery and co-operating like a bayonet joint .with counter teeth 0 provided on an extension p of the cylinder.

The turning movement of the piston slide valve I required for locking and unlocking it is efiected by two cams r 1 which are mounted on the cam shaft 2' on both sides of the main actuating cams q and are displaced from one. another by 180 degrees, and by means of two connecting links s s (see Figure 2). 1

The described two-stroke engine operates as follows: After injection of the fuel into the working cylinder, which has begun shortly before the working pistone has reached the upper dead center position, as illustrated in Figure 1, expansion of the gases of combustion takes place during the downward stroke of the working piston 6. Shortly before the latter uncovers the inlet ports 0, the outlet ports d are uncovered by the piston slide valve 1. After the scavenging action has been terminated, the outlet ports d are covered again, whilst the inlet ports still remain open. Now charging and compression of the fresh air takes place. j

During the compression stroke of the working piston e and particularly during the subsequent combustion as well as during the first part of the expansion of the gases of combustion the end surface of the piston slide valve which here forms the cylinder cover, is exposed to very high pressure which in the present embodiment equals the pressure acting upon the end surface of the working piston e. In order totake up this presv sure, according to the invention after the outlet ports '11 have been covered,that is, shortly before the compression begins, the piston slide valve 1 while in its lower dead center position is turned by means of the cams r 1' and through the intermediary of rods s 8 to such an extent, that its teeth 11 exactly register with the companion teeth 0 of the cylinder extension 12. In this locked position the piston slide valve ,1 under theload of the pressure prevailing in the working cylinder immediately abuts against the extension p fixed to the cylinder body a. Hence, the lines of force pass only through fixed parts of the engine, whilst the whole actuating gear of the piston slide valve f, inclusively of the link mdi- -rectly fixed to the piston slide valve j and the bearings oi the former, are completely relieved from the high pressure prevailing in the cylinder during the period of time the piston'slide valve f is locked as described hereinbefore.

, Before the outlet ports (1 are opened again, the piston slide valve f is turned back to initial position in which during the subsequent upward stroke the teeth n can pass with sufficient clearance between the fixed companion teeth 0.

The gear of the piston slide valve is designed in such a manner that only very small power is required for the'locking and unlocking turning motions of the slide valve. This is obtained by the main driving cam q on the downward stroke, that-is, previous tothe locking movement, moving the piston slidevalve downwards to suchan extent, that thereji's a certain clearance between the teeth 11 and-[the companion teeth in the direction of stroke of the valve qpnsequently in this position the piston slide valve f is turned into the locking position without anysubstantial friction. The configuration of the respective cam, further, is such that the following section of its operating surface recedes somewhat, so that the teeth n of the piston slide valve 1 under the action of the pressure increasing during the compression come to abut against the fixed teeth 0. Upon unlocking the operation is inverse, that is, the cam moves the piston slide valve j a small distance downward against the pressure prevailing in the cylinder, which pressure is comparatively low in the last section of the expansion period of the gases of combustion, so that again clearance is formed between the teeth 11 and the teeth 0, before the piston slide valve 1 is turned back by the same amplitude.

While in the embodiment described hereinbefore the whole piston slide valve is turned'to' the locking and back to unlocking position, the piston slide valve f of the second embodiment shown in Figures 3 and 4 is locked by means of a ring t rotatably mounted on the cylinder. Like in the first embodiment the piston slide valve 1 has teeth n which co-operate with teeth 0 provided on the rotatable ring it. The latter is turned by two rods u n similar to the rods s s of first embodiment, but provided with rack teeth engaging teeth 0 '0 on the ring t. These rods are actuated by two cams r 1 mounted on the cam shaft 1' and relatively displaced by 180. In the locked position of the piston slide valve f the ring tunder the action of the pressure prevailing in the working cylinder, abuts against the cylinder extension 9 which is fixed to the cylinder and has a suitable configuration. Sincethe piston slide valve in this arrangement is not turned, but executes only a reciprocating motion, actually a simple link connection between' the slide valve I and its connecting rod m would sufiice.

In this embodiment the acceleration forces to be exerted by the cam shaft 1' for locking the piston slide valve f are smaller than in the firstdescribed embodiment, since the rotatable ring t has a much smaller mass than the piston slidev valve j of Figures 1 and 2. This is of advantage in particular with engines of large size in which the piston slide valve has a corresponding great weight.

The invention can be applied also to engines in which the longitudinal .scavenging action takes place in inverse sense, that is, in which'the inlet ports are controlled by the piston slide valve disposed in the cylinder head, whilst the outlet ports are controlled by the working piston. Furthermore, instead of a piston slide valve an annular slide valve having afixed central body may be provided, in order to allow of a central injection of the fuel from above. Finally, the invention can also be applied with the same advantage to four stroke cycle engines the inlet or outlet ports of whieh'are controlled by slide valves.

What I claim is:- p

1. In an internal combustion engine, a cylinder, 2. piston in said cylinder, a slide valve in said cylinder opposed to the head of said piston, said cylinder having ports controlled by. said slide valve, mechanical means for reciprocating said slide valve in synchronism with the movement of said piston, .and means for intermittently locking said slide valve to said cylinder in a predetermined position in which said ports are covered by said valve during a period beginning prior to and continuing through the time of greatest pressure upon said valve.

2. In an internal combustion engine, a cylin der, a piston in said cylinder, a slide valve in said cylinder opposedto the head of said piston, me-

chanical means for reciprocating said slide valve in synchronism with the movement of said piston, said cylinder having ports controlled by said slide valve, interlocking stops on said valve and said cylinder for locking said valve against sliding movement, and means for intermittently engaging said stops during a period beginning prior to and continuing through the time of greatest pressure upon said valve and then disengaging said stops.

3. In an internal'combustion engine, a cylinder, a piston in saidcylinder, a slide valve in saidv cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide valve, interlocking teeth on said valve and said cylinder, and means for relative angular movement of said teeth to bring them into and out of alinement, said teeth being adapted to slip past each other in one relative position to permit said valve to slide.

4. In an internal combustion engine, a cylinder, a piston in said cylinder, a slide valve in said cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide valve, means comprising a cam shaft for reciprocating said slide valve, interlocking stops on said valve and said cylinder, and means controlled by said cam shaft for engaging said stops during a period beginning prior toand continuing through the time of greatest pressure upon said valve and then disengaging said stops.

5. In an internal-combustion engine, a cylinder, a piston in said cylinder, a slide valve member in said cylinder-opposed to the head of said piston, mechanical means for reciprocating said slide valve in synchronism with the movement of said piston, said cylinder having ports controlled by said slide valve member, a locking member on said cylinder, said slide valve member having stops engaging said locking member to prevent the valve member from sliding, and means for relatively turning said members to engage said stops during a period beginning prior to and continuing through the time of greatest pressure upon said valve and then to release said stops.

6. In an internal combustion engine, a cylin der, a piston in said cylinder, a slide valve member in said cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide ,valve member, a locking member on said cylinder, said slide valve member having stops engaging said locking member to prevent the valve member from sliding, and means operating in unison with the movement of said piston to reciprocate said slide valve member and to turn one of said members with respect to the other, first to engage said stops with said locking member in the inner position, 0'! said slide valve member during a period beginning prior to and continuing through the time of greatest pressure upon said valve, and then to disengage said stops to allow said slide valve member to move outward.

7. In an internal combustion engine, a cylinder, a piston in said cylinder, a slide valve in said cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide valve, mechanical means for reciprocating said slide valve in synchronism with the movement of said piston, a rotary locking member on said cylinder, and stops on said slide valve adapted to be blocked by said locking member in one position of the latter during a period beginning prior to and continuing through the time of greatest pressure upon said valve, in order to prevent said valve from sliding, said stops being re-. leased when said locking member is moved to another position.

8. In an internal combustion engine, a cylin der, a piston in said cylinder, a slide valve in said cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide valve, mechanical means for reciprocating said slide valve in synchronism with the movement of said piston, a rotary locking member of" relatively slight mass on said cylinder, and stops on said slide valve adapted to be blocked by said locking member in one position of the latter during a period beginning prior toand continuing through the time of greatest pressure upon said valve, in order to prevent said valve from sliding, said stops being released when said locking member is moved to another position.

9. Inan internal combustion engine, a cylinder, a piston in said cylinder, a slide valve memberin said cylinder opposed to the head of said piston, said cylinder having ports controlled by said valve member, a locking member on said cylinder, means for relatively turning said mem bers, interlocking means on said members adapted to be engaged and disengaged by the relative rotation thereof, and cam means operating in unison to reciprocate saidslide valve memberand relatively to rotate said members, said cam means being adapted to move said slide valve member to a position .in which ,said interlocking means move freely to and from interlocking position and to release said slide valve member when said interlocking means are in operative position, whereby the full stress exerted upon said slide valve member is intermittently taken up by said interlocking means, thus relieving said cam means thereof.

10. In an internal combustion engine, a cylinder, a piston in said cylinder, a slide valve in der, a piston in said cylinder, a slide valve in,

said cylinder opposed to the head of said piston, said cylinder having ports controlled by said slide valve; mechanical means for reciprocating said 1 slide valve in synchronism with the movement of said piston, and'means for intermittently locking said slide valve to said cylinder at approximately the innermost limit of its reciprocation during a period beginning prior to and continuing through the time of greatest pressure upon.

said valve.

' FRITZ ERNST. 

